When is the best time to observe 32 Cygni?

32 Cygni is best observed from June through August, with peak visibility during July when it transits around midnight in the Northern Hemisphere.

Where is 32 Cygni located in the sky?

32 Cygni lies in the constellation Cygnus at right ascension 20h 15m and declination +47° 43′.

What telescope do I need to split 32 Cygni?

Splitting 32 Cygni requires an aperture of roughly 60 mm or larger — the components are separated by about 208.5″ at magnitudes near 4.0. The companion is about 4.4 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

32 Cygni — Double Star in Cygnus

Observable Double Star Good (47/100)

Sep: 208.5", Companion: mag 8.4

Magnitude 3.9–4.1^m DoubleStar Cygnus (Cyg) Visible

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Observe

1Physical Properties

Magnitude 3.98

Range 3.90 - 4.14

Period 1147 days

Variable Type Eclipsing Binary (Algol-type)

Spectral Type K3Ib+B3V supergiant

Star Color Red (B-V 1.52)

Distance 233 ly

2Position & Identifiers

RA 20h 15m 28.3s

Dec +47° 42' 52.0"

Constellation Cygnus (Cyg)

HR 7751

HIP 99848

HD 192910

Flamsteed 32 Cyg

Variable ID V1488 Cyg

SIMBAD

3How easy to split?

Primary 4.0 mag Companion 8.4 mag Separation 208.5″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Easy	Easy	Easy
150 mm Newton 150mm Newt.	Easy	Easy	Easy
Celestron C8 (203 mm SCT) C8 203mm	Easy	Easy	Easy

Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

4Visibility

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Best season Jun – Aug (peak: Jul)

5Light Curve

6Multiple Star System

Separation 208.5″

Companion Mag 8.4

Companion Sp B6V

Position Angle 175°

Star Colors A: Red B: Blue-white

Discoverer S 743

Separation over time

Measured 1824 → 2015 (191 y)

Separation drift 208.9" → 208.5" (-0.40")

Rate -0.0021" / y

PA drift 175° → 175° (+0°, +0.000°/y)

Essentially fixed on human timescales — the same view your grandchildren will see.

Measured from the WDS observational archive. No orbital solution has been derived — most likely the period is too long to fit an orbit to the available measurement arc.

Eyepiece View

Telescope Eyepiece

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32x Dawes: 1.9″ TFOV: 1.6°

Seeing

Scale Realistic = true angular size

A: 4.0 · B: 8.4 · Sep: 208.5″ · PA: 175° · N up, E right

Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″

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Size Comparison

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Spectral Classification

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Hertzsprung-Russell Diagram

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Stellar Lifecycle

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Blackbody Spectrum

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Stellar Absorption Spectrum

Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.

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Stellar Fusion

Discover

16Stellar Notes

Variable Star

EA 3.90 - 4.14V, 1147.4d. Period varies. Light var. outside eclipse. The K component may be slightly intrinsically | variable.

Spectroscopic Binary

1147.8d, K 17.0k/s, V0 -5.7k/s, msin3i 9.15, asini 256. Also 390d suspected. Unresolved by speckle | interferometry. SKYLAB indicates cool star with hot companion.

Spectral

Also classified K5Iab + B4IV-V and K3II + B9:V.

Alternative Names

Originally called Omicron2 Cyg in GCVS, the name has been changed to V1488 Cyg because of much confusion as to | which star is Omicron1, which Omicron2. See HR 7730.

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